AlkaliAggregate Reaction (AAR) of Concrete Structures

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PDF Numerical Modeling of Orthotropic Concrete Expansion Due

Department of Civil Structures, Institute of Technology for Development - LACTEC . Abstract. The alkali-aggregate reaction (AAR) in concrete structures consists in a chemical deleterious reaction between alkalis liberated during hydration of cement and reactive min-erals present on aggregates.

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CONCRETE TECHNOLOGY Diagnosis and Control of Alkali

hydroxides in concrete.The reactivity is potentially harmful only when it produces significant expansion (Mather 1975).This alkali-aggre-gate reactivity (AAR) has two forms—alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR, sometimes called alkali-carbonate rock reaction, or ACRR).ASR is more often a concern than ACR

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RILEM Recommendations for the Prevention of Damage by

RILEM Recommended Specification: AAR-7.3 Preliminary International Specification to Minimise Damage from Alkali-Aggregate Reactions in Concrete—Part 3: Concrete Dams and Other Hydro Structures. Pages 155-168. Nixon, Philip J. (et al.)

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Leandro F.M. Sanchez | Faculty of Engineering | University

Moreover, he also currently participates in several technical committees worldwide such as ACI (201-durability; 236-materials science of concrete), RILEM (avoiding alkali-aggregate reaction in concrete structures; alkali-aggregate reaction prognosis) and IBRACON (alkali-aggregate reaction; concrete durability).

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PDF E ect of Alkali-Aggregate Reactions in Concrete Dams Using

concrete, is a catalyzer in this reaction. AAR causes concrete expansion, micro cracks and, nally, visible cracks in the concrete. Because water is required for continuance of the reaction, in dams, mass concrete, where humidity is at its extreme, the reaction can continue during the age of the structure. Over a long

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PDF Modelling of Alkali-aggregate Reaction Effects in

Chemical deterioration in the form of alkali-aggregate reaction (AAR) is a slow-evolving but progressive process leading to expansion and cracking of concrete, and to costly maintenance interventions.

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CiteSeerX — MODELLING OF CONCRETE STRUCTURES AFFECTED BY

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Alkali Aggregate Reaction (AAR) and Delayed Ettringite Formation (DEF) cause expansion of the affected concrete that generally leads to cracking and decrease of its mechanical properties.

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PDF Spillways Affected by Alkali-aggregate Reaction : Two Case

distress caused by alkali-aggregate reaction (AAR) in some concrete structures. This is especially common for some of the first generation dam structures, in Quebec, that were built before the 1940's. Damage to concrete caused by AAR reaction includes expansion causing cracking of the surface but it

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Guide to the Evaluation and Management of Concrete

CSA A864, 1st Edition, 2005 - Guide to the Evaluation and Management of Concrete Structures Affected by Alkali-Aggregate Reaction This Guide has been written by Canadian experts on the diagnosis and treatment of concrete structures affected by alkali-aggregate reaction (AAR).

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Alkali-Aggregate reaction in Western Cape concrete

Alkali-aggregate reaction, AAR, was first discovered in 1938 by Stanton in the USA. Subsequently, researchers across the globe have reported incidences of the reaction with different aggregates in their respective countries. The reaction entails the interaction between reactive silica found in aggregates and alkali in the pore solution of concrete.

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RILEM State-Of-the-Art Reports: RILEM Recommendations for

Find many great new & used options and get the best deals for RILEM State-Of-the-Art Reports: RILEM Recommendations for the Prevention of Damage by Alkali-Aggregate Reactions in New Concrete Structures : State-Of-the-Art Report of the RILEM Technical Committee 219-ACS ( , Hardcover) at the best online prices at Free shipping for many products!

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PDF Alkali-Aggregate Reaction in Concrete

Testing of Australian Concrete Mixtures for Alkali-Silica Reaction Potential and Calibration with Field Performance of Structures Carse.A 247 Alkali-Aggregate Reaction Assessment in Kansas Clowers, K.A., Abou-Zeid, M.N 257 Evaluation of The Potential Alkali-Reactivity of Concrete Aggregates: Performance of Testing Methods and A Producer's Point

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PDF Diagnosis of concrete structures distress due to alkali

Key words: alkali-aggregate-reaction, diagnosis, concrete structure. 1. Introduction Some of the minerals present in aggregate may react with sodium and potassium hydroxides from the concrete pore solution. Alkali-aggregate reaction (AAR) occurs either as alkali-silica reaction (ASR) or alkali-carbonate reaction (ACR).

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PDF] Alkali-Aggregate Reaction and Structural Damage to

Description: Since AAR was first identified in 1940, it has been a subject dominated by studies of the mineralogy of AAR-susceptible aggregates, the chemistry of the AAR and related reactions and laboratory tests used to diagnose AAR and predict potential future swelling. Civil and structural engineers have found the literature bewildering and

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RILEM Recommended Specification: AAR-7.3 Preliminary

Oct 01,  · RILEM Recommendations for the Prevention of Damage by Alkali-Aggregate Reactions in New Concrete Structures pp 155-168 | Cite as RILEM Recommended Specification: AAR-7.3 Preliminary International Specification to Minimise Damage from Alkali-Aggregate Reactions in Concrete—Part 3: Concrete Dams and Other Hydro Structures

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Chemo-Damage Model for Concrete Anisotropic Expansion

A chemo-damage model for concrete affected by alkali-aggregate reaction (AAR) is presented. Redistributing weights, determined by the applied stresses in the concrete, are introduced to control the anisotropic expansion of the AAR-affected concrete. Accelerated tests are analyzed using the proposed model. The computed strains of the specimens are compared with the experimental measured strains.

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Numerical Modeling of Orthotropic Concrete Expansion Due

The alkali-aggregate reaction (AAR) in concrete structures consists in a chemical deleterious reaction between alkalis liberated during hydration of cement and reactive min-erals present on aggregates.

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Central Soil & Materials Research Station New Delhi

Monograph on alkali Aggregate Reaction is a first publication of CSMRS. In recent years, distress due to Alkali -Aggregate Reaction (AAR) in concrete structures has increased. It is well known that the locally available aggregates are mostly reactive and prone to deleterious reaction.

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PDF Concrete Expansion - R

Concrete expansion due to Alkali-Aggregate Reaction (AAR) was diagnosed in 1991 as the root cause of concrete movement and ensuing generator and structural problems. A proactive concrete rehabilitation program was implemented from 1993 to 2000 to mitigate the effects of AAR induced concrete expansion and repair the concrete structural damage.

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PDF Engineering Field Tests for Alkali-Aggregate Reaction

2 | REVIEW OF ALKALI-AGGREGATE REACTION (AAR) According to the literature, AAR is a chemical reaction between some constituents present in certain types of aggregates and alkali components that are dissolved in the solution in concrete pores, which are usually derived from cement. The occurrence of this type of reaction is

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Concrete modelling for expertise of structures affected by

Apr 01,  · 1. Introduction. Alkali aggregate reaction (AAR) affects numerous civil engineering structures and causes irreversible expansion and cracking. AAR is a chemical reaction between the reactive siliceous phases of aggregates and alkalis of the cement. The aggregate swelling (due to its cracking) and the product of the reaction (gel) leads to the

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PDF WHITE P APER FlatlineAlkali-Silica Reaction

concrete and the aggregate, signi˜cantly shortening the engineered lifespan of the infected structure. Once the alkali-silica reaction kindles within concrete—triggered by the collision of alkali, silica, moisture, and calcium hydroxide (a deleterious byproduct spawned by the Portland cement+ water hydration reaction)—it cannot be stopped.

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ASTM C1778-19 Standard Guide for Reducing the Risk of

1.1 This guide provides guidance on how to address the potential for deleterious alkali aggregate reaction (AAR) in concrete construction. This guide addresses the process of identifying both potentially alkali-silica reactive (ASR) and alkali-carbonate reactive (ACR) aggregates through standardized testing procedures and the selection of mitigation options to minimize the risk of expansion

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Diagnosis of concrete structures distress due to alkali

Key words: alkali-aggregate-reaction, diagnosis, concrete structure. 1. Introduction Some of the minerals present in aggregate may react with sodium and potassium hydroxides from the concrete pore solution. Alkali-aggregate reaction (AAR) occurs either as alkali-silica reaction (ASR) or alkali-carbonate reaction

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Proceedings of the 12th International Conference on Alkali

problems on alkali-aggregate reactions of dam concrete in china; late-expansive alkali-silica reaction in the ohnyu and furikusa headwork structures,central japan; deterioration by alkali-aggregate reaction of concrete in sanyuan flyover bridge; traic o dam-the evolution of the alkali aggregate reaction (aar

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Modeling the Structural Effects of Alkali-Aggregate

The structural effects of alkali-aggregate reactions (AAR) are briefly described, and the implications of these effects on the modeling of reinforced concrete s

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